Biomass construct for erosion control and structures

ABSTRACT

In one aspect there is provided a construct, mound, layer or brick which offers utility as an erosion control medium formed primarily from a blend of biomass, cementitious binder and water. In another aspect there is provided a construct, mound, layer or brick, which offers utility as a construction medium. Also provided are processes by which an aggregate of woody biomass (a blend of chips, particles and pieces), and a cementitious binder slurry can be applied by manual methods or spray applied by mechanical means. Upon drying the biomass construct conforms and binds to a ground surface providing a hard porous medium capable of adhering to a large variety of ground surfaces and to terrain of varied slope, pitch and constitution.

The invention is directed to ground surface covers, including methodsfor producing said devices, the devices themselves and applications forsaid devices. The invention satisfies a need for environmentallyfriendly ground surface covers which can be easily anchored to terrainof varied slope, pitch and constitution and offering exemplaryperformance as an erosion control applications. The term constitution inthe context of this patent application refers to different terrainscomposed from a wide variety of soils, rocks, organic materials,vegetation, biomass and a wide range of moisture contents.

Included in the disclosure are exemplary devices, systems, and methods,embodiments of which can be useful for controlling erosion, treatingrunoff, removing pollutants, remediating environmental damage,protecting plants, establishing vegetation, protecting ecosystems,and/or restoring waterways and/or other riparian areas, buildingstructures such as roads, work spaces, buildings or berms and otherwiseorganizing biomass into a useful product.

In the context of this patent application biomass refers primarily tobiomass materials such as those associated with, but not primarilyharvested or used in logging operations, road construction, buildingconstruction, agriculture operations, thinning operations, firesuppression, post fire debris and land fill debris. It should be notedthat the innovation can be practiced using single or multiple sources ofbiomass.

It is emphasized that this abstract is provided to comply with the rulesrequiring an abstract that will allow a searcher or other reader toquickly ascertain the subject of the technical disclosure. This abstractis submitted with the understanding that it will not be used to limitthe scope or meaning of the claims.

BACKGROUND

Many of today's logging, construction, road building, landfill and underdeveloped landscapes can benefit from erosion control, wind or dustbreaks and/or infrastructure such as roads, buildings, landing stripsand work zones. Many of these locations are distant from constructionmaterial sources, necessitating transportation of structural materials,construction equipment and trained personnel to meet the raw material,processing, construction and installation requirements. Transportationrequirements can be capital intensive, inefficient, require significantamounts of man-hours, capital expenditure, produce undue amounts ofgreen house gases and can be a limiting factor to the implementation oferosion control media.

Transporting raw materials and machinery from distant locations to anerosion prone area can introduce pollutants and biological or chemicalspecies not native to the application site or work zone. The inventiondisclosed offers an erosion control system, methods for producing saidsystem and applications for said system utilizing locally availablebiomass materials processed to offer exemplary performance as an erosioncontrol barrier, construction medium or containment system. Though thefollowing discussion speaks primarily to erosion control barriers, itshould be understood that the invention is not limited to erosioncontrol media but also offers exemplary utility in other structuralapplications. Structures produced can be either permanent orsemi-permanent. Permanent structures in the context of this applicationare those structures build to last a minimum of twenty years.Semi-permanent in the context of this application means lasting orintended to last for one week to five years.

Erosive wear occurs when a surface is exposed to the movement of aflowing liquid. Erosive wear increases dramatically if the flowingliquid has a solid material suspended in it. Particles and pieces ofdebris within the flowing liquid impact an exposed surface and impartsome of their kinetic energy to said surface. If the energy issufficiently high, the kinetic energy of the impacting particles cancreate significant tensile residual stress in the exposed surface.Repeated impacts cause the accumulation of tensile stress in the pronesurface leaving the exposed surface brittle, leading to cracking, cracklinkage and eventually gross material loss. Material loss results in areduction of vegetative growth, a reduction in the habitat suitable formicroorganisms, and the deleterious effects commonly associated with themovement of materials into bodies of water and the aquifer.

As a result, erosion control techniques and devices are often requiredto inhibit soil movement in areas undergoing logging operations,reforestation, road construction, waterway construction, building andhome construction, mine or landfill sites or other sloped areas that areprone to erosive wear. These techniques commonly include, for example,the installation of perimeter barriers such as straw bales, silt fences,compost filter berms, erosion barriers or most recently systemscomprised of biomass and synthetic fibers. The following text relates torelated art, which is not admitted to be prior art with respect to theinvention by its mention in this Background Section.

Straw bales have been shown to be effective at providing some measure oferosion control. Straw bales are typically placed around a designatedarea to physically impede the flow of water and water born solids. Whilethese bales are relatively inexpensive to purchase and easy to install,they are unsightly, must be transported to the site being eroded andmust be removed after soil stabilization has been effected. Furthermore,the bales may be displaced by heavy water run-off events, therebyrendering them ineffectual for controlling soil movement.

Silt fences are also known to impede soil movement in erosion proneareas. However, they are aesthetically unpleasing, must be removed afteruse and require a means of securement to the eroding surface. Inaddition, as compared with other erosion control techniques,construction and installation of silt fences is expensive.

In contrast, U.S. Pat. Nos. 6,921,484, and 6,709,202 describe filterberm erosion barriers comprising a biodegradable “sock” filled with abiodegradable material. Said socks are filled using conventional blowertechniques. The sock is composed of material, such as burlap, thatnaturally rots and decomposes. Thus, when the sock decays, it mergesinto the surrounding soil and thus leaves a minimal trace. The materialsused to fill said socks can be pre-seeded compost, which allow desiredvegetation to grow from the compost into the underlying soil.

Though compost filter berms must be transported to the worksite therebyincurring costs and equipment use, they are relatively inexpensive toinstall and need not be removed. These berms physically filter settleable solids from water runoff, and can provide an environment formicroorganisms capable of degrading organic compounds and bindingpollutants. Furthermore, compost filter berms can promote seedestablishment and plant growth. Wattles must be properly installed withthese systems or they can concentrate sheet flows resulting in a rapidrate of erosion. These systems must be embedded into the soil byexcavating a shallow trench and backfilling, leading to extensive laborrequirements for installation. Compost filer berms are also known tocatastrophically fail in major water events and suffer from ultravioletdegradation resulting in premature failure and distribution of the bermconstituents. Said filter berms can be expensive to install andtransport and are known to introduce non-native species to applicationenvironment. The berms are also known to not intrinsically bind to theerodible surface and known to divert water around said berm and undersaid berm thereby propagating the erosive behavior to a differentlocation or focusing it to a specific location. Therefore they provideless than ideal erosion control. Compost filter berms require wattles,which are known to fail by spillway effects, undercutting, and flankingfurther exacerbating failure mechanism resulting in erosion.

Recently, the industry has developed blanket-type products called turfreinforcement constructs such as that expressed in U.S. Pat. No.4,372,705 which describes an articulated construct comprising aplurality of blocks which interlock in a three dimensional fashion whichallow a construct formed of the blocks to conform to changes in terrain.Though this technology conforms to the terrain, conformation is limitedto the size of the blocks used in the construct. U.S. Pat. No. 3,597,928discloses the use of porous flexible supporting sheets with blocksplaced on said sheets. Each construct consists of a plurality of blockswith drainage passageways, which allow the movement of water through theblocks facilitating vegetative growth through the blocks. The constructsare secured to the sheets by adhesive means resulting in a structurallysound erosion control medium. Turf reinforcement constructs areexpensive, require a significant amount of labor to install and relyupon transportation to bring the devices to the work zone. Furthermore,these constructs are not amenable to excessively steep slopes, narrowravines or highly irregular slopes. Though these systems conform toterrain they are also limited in conformation to the size of theinterlocking blocks.

The industry has also developed earthen containment reinforcementsystems such as that described in U.S. Pat. No. 7,563,057 to conveywater and withstand designated loads. While such turf reinforcementconstructs do little to reduce or mechanically dissipate the energy ofrunoff water energy themselves, their installation allows for the growthof vegetation, which, in turn, mechanically reduces energy associatedwith runoff water. Such blankets are typically three-dimensional,flexible constructs constructed of plastic webbing. The open weave ofsuch constructs allows vegetation to grow through the barrier. Thecombination of a mechanical stable structure and open weave designresults in a significant synergistic effect, with the capacity to carrymuch greater velocity and sheet force loads because roots and stemsassociated with the growing vegetation are reinforced by the construct.

Although turf reinforcement and erosion control constructs have numerousadvantages over the prior efforts in terms of reducing erosion, it isoften difficult to securely mount these types of constructs in anerosion prone area and they are not applicable in steep or highly uneventerrain. Another draw back to turf reinforcement and erosion controlconstructs of this type is that they typically require complex anchoringsystems and multiple personnel to install. Once installed these systemscan also suffer from excessive movement between the construct and theground thereby allowing erosive flow beneath and around the construct,resulting in undesired erosion. Play or movement in these systems is amajor failure mechanism in steep terrain, highly uneven terrain, terrainalready suffering from erosion or terrain where it is difficult toproperly secure said erosion control devices. If the movement is chronicor becomes substantial, the anchor can become dislodged, allowing theconstruct to move away from the erosion susceptible surface or failcompletely, thereby defeating the purpose of the construct. Thesesystems also require significant time and cost to transport the devicesto the work site. Another significant draw back is that many of thesesystems are produced from environmentally unfriendly materials.

In order to provide an alternative approach, certain pre-blended mulchproducts have been introduced into the marketplace. U.S. Pat. No.5,476,711 describes a fiber blending system, which forms a constructproduced from a combination of cellulosic and synthetic fibers.According to U.S. Pat. No. 5,476,711, the method disclosed describesfiberizing cellulosic materials into cellulosic fibers in a fiberizer,volumetrically metering an amount of synthetic fibers, and injecting themetered amount of synthetic fibers into the cellulosic fibers. Thecellulosic fibers are blended with the metered amount of syntheticfibers in a blending chamber to form a fiber blend. The fiber blend isthen dispersed through a fiber disperser. A third type of fiber may alsobe mixed with the dispersed fiber blend. The dispersed fiber blend iscollected as a construct on a fiber collector to provide a construct ofblended cellulosic and synthetic fibers. The construct may be thermobonded and sandwiched between a facing sheet and a backing sheet.

U.S. Pat. No. 5,942,029 describes a water absorbent fiber mulch madefrom natural and crimped, synthetic fibers that are intimately mixedtogether to form the fiber mulch. Said fiber mulch is mechanicallybonded into an open weave system produced by the entanglement of thecrimped synthetic fibers with one another and said natural fibers. Theentanglement holds the mulch together in a construct, which issufficiently permeable to air and porous enough to allow seedlings togrow up through said mulch. A water-absorbent polymer-based constructionmaterial is dispersed throughout the fiber mulch to increase its waterabsorption capacity. Similar mulch products are found in U.S. Pat. No.5,779,782 and U.S. Pat. No. 5,741,832.

Systems that promote seed retention and growth have also been developed,such as that described in U.S. Pat. No. 7,384,217. U.S. Pat. No.7,384,217 describes a system and method for promoting vegetative growthon a steeply sloping surface. The patent describes a series of syntheticand geosynthetic layers, seeded compost and an anchoring system.Vegetation grows in the compost construction material establishing aroot system thereby stabilizing the erosion prone slope.

Not withstanding the aforementioned products in the field, there remainsa need in the art for an erosion control device which is easily producedand deployed, uses locally sourced construction materials minimizing theneed for transporting erosion control media, a device which conforms andbonds to an erosion prone ground surface regardless of slope, terrain orconstitution without the requirement of a separate retention system.Furthermore, there remains a need in the art for an erosion controlmedium, which can be produced in remote locations with a minimum ofmechanical equipment and personnel. Furthermore yet, there remains aneed in the art for an erosion control device that can convert locallysourced biomass containing biota specific to the site, which isimportant in re-establishing natural biological functions, to a usefulconstructive media. Furthermore yet, there remains a need in the art foran erosion control medium, which requires a minimum of installation andmaintenance during the lifetime of the constructed system that can beapplied in a continuously variable embodiment in response to thevariable requirements of the landscape. Furthermore yet, there remains aneed in the construction, timber and fire suppression industries tosequester biomass in order to reduce fire danger.

The difficulties encountered in prior efforts discussed hereinabove aresubstantially eliminated by the present invention.

An objective of the invention is to provide a biomass construct,produced from locally sourced biomass converted to a value addedconstruction material.

A further objective of the invention is to provide a biomass construct,containing local biota thereby enabling improved integration into theenvironment without introducing foreign biota, microorganisms orpollutants.

A further objective of the invention is to provide a biomass construct,which reduces the energy associated with erosive fluid flow whilemaintaining fluid flow through the biomass construct.

A further objective of the invention is to provide a biomass construct,which is produced and installed in an environmentally friendly manner.

A further objective of the invention is to provide a biomass construct,which is comprised from organic materials.

A further objective of the invention is to provide a biomass construct,which does not require the addition of synthetic fibers, rods, sheets orother synthetic materials.

A further objective of the invention is to provide a biomass construct,which is produced from a minimum of transported materials thereby vastlyreducing the environmental impact and costs associated with thetransportation of materials.

A further objective of the invention is to provide a biomass construct,which is lightweight and low cost.

A further objective of the invention is to provide a biomass construct,which is easy to install.

A further objective of the invention is to provide a biomass construct,which does not need to be removed once installed.

A further objective of the invention is to provide a biomass construct,which easily accommodates various depths, pitches, angles and slopes inthe application terrain.

A further objective of the invention is to provide a biomass construct,which allows for quick installation without the need for heavy or costlytools or machinery.

A further objective of the invention is to provide a biomass constructthat can be installed with no need to excavate, compact, pre-treat orotherwise disturbance the application surface.

A further objective of the invention is to provide a biomass construct,which allows greater securement to a surface without the need ofsecurement beyond the biomass construct itself.

A further objective of the invention is to provide a biomass construct,which is durable and long lasting.

A further objective of the invention is to provide a biomass construct,capable of being used as a structural component for roads, buildings,landing strips or berms.

A further objective of the invention is to provide a biomass construct,which provides an environment amenable to plant and microorganismgrowth.

A further objective of the invention is to provide a biomass construct,which has sufficient porosity to allow water to follow an impeded butminimally diverting course.

A further objective of the invention is to provide a biomass construct,which can be sprayed from a blower, applied by hand, applied withbuckets and spilled from a container.

A further objective of the invention is to provide a biomass construct,which can be produced in remote locations with a minimum oftransportation requirements.

A further objective of the invention is to provide a biomass construct,using locally available biomass.

A further objective of the invention is to provide a biomass constructand method of use that is simple to apply.

A further objective of the invention is to provide a biomass construct,which can be produced and applied in isolated environments. Isolated inthe context of this patent application refers to areas which aredifficult to reach for conventional mechanical application equipment.

A further objective of the invention is to provide a biomass construct,which reduces the risk of fire by sequestering biomass into bound andcoherent biomass products.

A further objective of the invention is to provide a biomass construct,which impedes the evaporation of soil moisture into the atmosphere.

A further objective of the invention is to provide a biomass construct,which is not confined to a specific form, rather conforms to thedeposition surface and desired shape of the final construct.

A further objective of the invention is to provide a biomass construct,which is produced from a variety of sources such as but not limited torestoration, lumber, construction, agricultural, biomass, pulp, paperand pallet byproducts.

A further objective of the invention is to provide a biomass construct,which can be made by hand or by machinery with no change in performance.

A further objective of the invention is to provide a biomass construct,which can be used as a final cover for landfill, agricultural, fire andconstruction sites.

A further objective of the invention is to provide a biomass constructand method of making same.

A further objective of the invention is to provide a biomass constructand method of installation of said construct.

SUMMARY

The present invention is directed to an improved biomass construct andmethod of making the same. The present invention is directed to aprocess for preparing a solid biomass construct for application to aground surface in order to reduce erosion that satisfies the need to beenvironmentally friendly, easy to apply and capable of being secured toa wide variety of terrains. An erosion control barrier having featuresof the present invention comprises the steps of formulating acementitious binder, thoroughly mixing said cementitious binder in aquantity of water so as to form a cementitious binder slurry. Addingsaid cementitious binder slurry to a quantity of biomass and thoroughlymixing said slurry and said biomass together so as to substantially coatsaid biomass with said slurry. Applying said slurry coated biomass tosaid ground surface and allowing said slurry coated biomass applied tosaid ground surface to cure into a solid biomass construct. Said biomassconstruct provides a cost effective, easily manufacturable constructionmaterial with applications in erosion control, airborne particulatecontrol, fire suppression and as a hard and durable surface formachines, livestock and personnel. Said biomass construct furtherprovides as an impact barrier for vehicles or shooting ranges and as ademarcation or marker system visible from large distances or heights.Said invention further offers as a medium for controlled burns and amethod to organize and sequester biomass into a value added constructionmedium. The present invention further offers utility as a buildingconstruction material for housing, storage, wind and snow barriers.

To practice the innovation, a cementitious binder slurry is prepared ina suitable container. Additional additives can be mixed into saidcementitious binder slurry forming a binder additive slurry which ismixed to a homogeneous distribution. The cementitious binder additiveslurry is added to the mechanically refined or virgin biomass and mixedsuch that said biomass becomes coated with said slurry.

Typically, the biomass water mixture is formed within a mix tank,wheelbarrow or container. Commonly, said mix tank is equipped withmechanical agitators or circulation pumps power by a motor. It should benoted that the innovation disclosed is amenable to mixing done by handwithout the requirement for any mechanical assistance. The coatedbiomass system can now be applied to an application surface by manual ormechanical means. Once applied, the mixture dries into a cured andhardened structure providing exemplary physical characteristics usefulin applications such as erosion barriers or construction materials.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of promoting an understanding of the principles of thepresent invention, reference will now be made to the embodimentsillustrated in the drawings and specific language will be used todescribe the same. It will nevertheless be understood that no limitationof the scope of the invention is thereby intended. Any alterations andfurther modifications in the illustrated device, and any furtherapplications of the principles of the invention as illustrated thereinbeing contemplated as would normally occur to one skilled in the art towhich the invention relates are also included.

FIG. 1 shows a side elevation view of a cured biomass constructembodiment of the invention that incorporates a log within saidconstruct.

FIG. 2 shows a side elevation view of a biomass preparation process usedto produce an embodiment of the invention.

FIG. 3 shows a side elevation view of an uncured biomass systemembodying the invention being blown onto an eroded ground zone.

FIG. 4 shows a side elevation view of a biomass construct embodiment ofthe invention incorporated into eroded ground

FIG. 5 shows a top view of a biomass construct embodiment of theinvention applied to a sloped area.

FIG. 6 shows a top view of a biomass construct embodiment of theinvention applied to a series of ravines.

DESCRIPTION

The following description describes the innovation in terms of itsapplication as an erosion barrier though it should be understood thatthe biomass construct described and the methods of preparation expressedare applicable to other applications as discussed elsewhere in thispatent. Reference will now be made in detail to production,implementation and embodiments of the invention, examples of which areillustrated in the accompanying drawings.

For the purposes of this specification, a biomass material (2) isdefined as material from a plant, tree, shrub, grass, vegetation oragricultural byproduct. One of the distinguishing factors of theinnovation is that it can accommodate a large range of biomass shapes,sizes and size distributions. Irregular shapes including those commonlyassociated with chipping, thinning, cutting, crushing or breaking uplarger pieces of wood in to smaller pieces of wood can be used toproduce said biomass construct. Angular, rounded and irregular piecescan be used separately or in combination to produce said biomassconstruct.

Biomass material (2) of different sizes and size distributions can becombined in the practice the innovation. Very large pieces of biomass,such as trees (4) can be incorporated into said biomass construct. Smallpieces of biomass such as grasses, wood chips, wood flakes or twigs (6)can also be used in the production of said biomass construct. Thevariety of shapes and sizes within the biomass construct assist inanchoring said construct to the ground (8).

Suitable biomass materials can be produced by several methods includingchopping, chipping, cutting, shaving, mulching, natural refining orgathering biomass within the suitable size ranges. Natural refining canalso occur or can be a result of the natural growth of the chosenbiomass. Sources for biomass materials include but are not limited toremnants from lumber operations, fire remnants, bamboo, tree and shrubclippings, urban waste such as pallets, demolition wood, saw millremnants, firewood operations and grasses.

Biomass materials of widely varying moisture content can be used inpractice of the invention. Moisture content from less than 5% to morethan 75% can be successfully processed into a high quality andfunctional biomass construct embodying the invention. Biomass withdifferent water contents can be used in a singular instance of theinvention. Water content is an important variable to consider in thepractice of this innovation.

When practicing the innovation on a dryer biomass, that is a biomasswith a small amount of water content, for example 10%, additional watermay be required to insure sufficient wetting of the biomass with the abinder containing slurry. Said binder containing slurry is shown in itscured form (10) in the accompanied figures as a coating around theindividual pieces of biomass. Biomass is considered to be sufficientlywet if 90% of the biomass surface area is coated with the water bindermixture during the mixing process. The biomass material usually formsthe predominant component in the blended product, comprising about 25%to about 90% by weight of the cured biomass construct. More preferably,the biomass material comprises between 50% to 85% by weight of the curedbiomass construct. The high concentration of biomass constructionmaterial provides the bulk required to form the biomass construct.

The surface area of the biomass material is an important parameter toconsider. As surface area increases, the adhesion and loading of thewater binder mixture also increases. Loading in this case refers to theamount of water binder mixture that adheres to the biomass material. Theincrease in surface area also increases the amount of contact betweenindividual biomass pieces resulting in increased physical strength andimproved adhesion characteristics in the cured biomass construct.Further, increased surface area can improve the permeability in theresulting cured biomass construct. Increasing the surface area alsoaffects the flow characteristics of biomass and coated biomass throughconveyance means. In particular, increased surface area has been foundto improve conveyance of water binder mixture coated biomass throughforced air assisted conveyance means as described later in this text.Increased surface area is most often accomplished by roughening throughwell-known techniques such as physical agitation of the type commonlyassociated with hammer milling or re-chipping processes. Chemicalroughening techniques are also known in the art. Increased surface areais predominantly a function of an increase in the amount of biomassfibers partially separating from the main biomass body and flattening,bending or further disconnection of said separated biomass fibers.Partial separation is defined as those fibers or groups of fibers thathave some percentage greater than 1% but less than 99% connected to alarger biomass body, the remainder of which is not connected to thebiomass body. It should be noted that increasing the surface area toomuch, could result in different performance attributes. For example, ifbiomass shavings or fines are used in the described process, additionalbinder may be required to achieve high quality cohesion.

The relative density of the biomass is not a major factor in the biomassconstruct's physical performance. The addition of a cementitious binder(12) produces a solid biomass construct by binding the biomass particlestogether rather than relying on the density of the biomass to producestructural integrity. The use of cementitious binders allows theutilization of a wide variety of biomass materials of varying density,size, width, and shape to produce the described biomass constructs.Materials such as grass, manure, wood chips, brush, bamboo, mulch,biomass left over from logging, road building or construction projectsand other biomass materials can be used to practice the innovation.

The biomass construct obtains the desired strength, hardness, resiliencyand longevity from the use of a cementitious binder, which upon curingbinds the individual biomass pieces into a solid biomass construct. Bybinder we infer an ingredient that is used to bind together two or morematerials in a mixture. Many different binders and binder formulationsexist. The two principal properties involved in the binding mechanismare adhesion and cohesion. Though both organic and inorganic binders canbe used, the preferred binder is cementitious in nature and can beeither insoluble such as cement, clay and lime or soluble. Preferredinorganic binders include but are not limited to magnesium oxysulfate,magnesium oxychloride, or magnesium phosphate. Within the text of thispatent, the use of the word binder and cementitious binder and theirplurals are to be considered one and the same.

The aforementioned binders have shown no toxicity in the quantities usedfor erosion control purposes. Regardless of which binder is used, thechoice of binder should not include those binders that re-dissolve oncethe biomass construct is allowed to cure. The binder comprises between10 weight percent to 75 weight percent of the blended biomass productdescribed herein. More preferably, the binder comprises between 15weight percent and 50 weight percent of the blended biomass.

Admixtures (14), such as boric acid, may be incorporated into the binderslurry. Boric acid is used to increase the amount of time the biomasscan be manipulated or handled before curing. Other additives (16) suchas natural or synthetic binders, tackifiers, dispersants, admixtures,flocculants, emulsifiers or de-flocculants can optionally be added tothe binder water mixture to improve the viscosity, density, workabilityor properties of the biomass slurry mixture, though they are notrequired to achieve a satisfactory product. Said additives are commonlyused to improve the consistency of binder slurries, promote distributionof additives or reduce the friction associated with solid materials in apump. These additives (16) can be used to prevent plugging of the pumpsand to aid in the adherence of the biomass construct to the applicationsurface.

The addition of foam (18) has been found to be beneficial in controllingthe adherence of the binder water slurry to said biomass surface. Theaddition of foam produces tiny bubbles in the binder water slurry,increasing its ability to adhere to surfaces. Increased adherence of thebinder results in increased binding of the biomass and improvesstrength, hardness and durability of the resulting cured biomassconstruct.

To produce said foam, a foaming agent, such as CreteFoam produced byRichway, is diluted with water and pumped through a foaming makingmachine. Foam making machines are known in the art. Said foam makingmachines process a foaming agent into a foam which can then be blendedinto a given binder slurry and mixed to a homogeneous distribution. Foamto binder slurry ratios varying in volume from 0.5-1 to 3-1 (foam-binderslurry), were found to improve binder slurry adhesion to biomass andground surfaces. More preferably, foam to binder slurry volumetricratios between 1-1 and 2-1 (foam-binder slurry), have been found togreatly improve binder slurry adhesion to biomass and ground surfaces.

The function of the binder (12) and any additional additives (16) ismultifold. In the binder slurry, the binder coats the biomass andincreases the viscosity of the slurry. The binder coated biomass has areduced friction coefficient, thereby reducing stress in any machineryused to prepare, process or convey said coated biomass. Further yet,binder increases the homogeneity of the resulting coated biomassmixture. The combination of reduced friction and increased homogeneityresult in the ultimate delivery of a relatively even and consistentmixture of coated biomass, which may be applied to a ground surface toform a biomass construct having a substantially homogenous distributionof biomass material. Further yet, the reduced friction also extends pumpand hose life and lowers the requirement for pumping energy. Theaddition of a cementitious binder further provides adhesion ofbiomass-to-biomass, biomass to soil and soil to soil in a biomassconstruct or an erosion control medium formed on a ground surface.

Binder slurry is prepared by thoroughly mixing a cementitious binder(12) in water (20) until it dissolves forming a cementitious binderslurry (22). Mixing can be accomplished by mechanical or manual means.Mechanical blending is most commonly used. If admixtures (14) oradditives (16) are required, they are added to the binder slurry oncethe binder is dissolved in said water. If additives are required,mechanical or manual blending is used to homogeneously distribute saidadditives within the binder slurry.

Mixing of the cementitious binder, admixtures, and additives is mostcommonly done by using a mechanical mixer of the type commonly used tomix paints, though it should be understood that manual mixing and othermixing techniques are known in the art and amenable to the practice ofthis innovation. In one example, an electric drill (24) and a mixingpaddle (26) of the type commonly used to mix paints and a five gallonbucket (28) was used to facilitate mixing. It should be understood thatmixing times can vary as a function of water temperature, the amountsbeing mixed, the means for mixing, elevation and the type of binderused. Mixing is considered complete when a substantially homogeneousmixture is produced. If additives or admixtures are to be included, theyare mixed into the binder slurry in a similar manner.

Upon homogenization of the binder slurry or binder additive slurry orbinder admixture slurry or foam containing binder slurry or anycombination thereof, termed for the purposes of this application, acementitious binder containing slurry (30) are added to the biomass suchthat biomass is coated with the binder slurry. Many mixing techniquesare known in the art including but not limited to manual mixing,mechanical mixers (32), cement mixers, auger mixers, tumble mixers andblower mixers and others which are known to mix multiple components atthe same time.

Mechanical mixing is predominantly used as it is known to providesufficient mixing. Sufficient mixing is one that reduces or preventsclumping of biomass and uneven dispersion of the binder containingslurry. Clumping of biomass and/or uneven dispersion of the binder cancause machinery to clog or breakdown. Clumping of biomass and/or unevendispersion of the binder containing slurry can result in weak spots inthe erosion control medium formed using the blended biomass product.Effective mixing helps to blend the different types of materials andshapes together and form the desired homogeneous distribution of themixed constituents.

Upon complete mixing of the binder containing slurry and biomass, theresulting coated biomass can be applied to the application surface.Application can be by manual or mechanically assisted means. If thebinder coated biomass (34) is to be applied by hand, the operator canposition said binder coated biomass (34) using a bucket or similarcontainer onto the application surface.

In another alternative, the binder coated biomass (34) can be applied bymechanical means, for instance by using a blower (40). A number ofdifferent types of blower mechanisms exist. By blower we refer to adevice that accelerates the biomass such that it is expelled at the endof the blower with sufficient velocity to be advantageously positionedon an application surface (42). One such example is a model BB302 barkblower produced by the Finn Corporation. These types of blowers canfacilitate addition of the cementitious binder containing slurrydirectly onto the biomass at the nozzle end of the blower using a staticmixing nozzle (44). Said static mixing nozzle (44) uses a ball valve(46) to supply a measured amount of the cementitious binder containingslurry via injection ports (48) to the static mixing nozzle (44). Thestatic mixing nozzle (44) fully coats the flowing biomass withcementitious binder containing slurry by turbulent mixing prior toexpulsion from the nozzle.

Said Finn bark blowers are usually operated at 10 PSI producing anairflow of 500 cubic feet per minute and carry up to 3 cubic feet perminute of biomass. Larger blower systems are known to exist and arecapable of airflows of 1500 cubic feet per minute at 15 PSI. It shouldbe understood that said binder coated biomass systems can be processedusing both smaller and larger blower systems than those described.

Once the coated biomass has been applied to the application surface, thebinder cures forming a durable biomass construct. The cured biomassconstruct is endowed with sufficient structural integrity to survivewater flow, environmental influences such as wind, rain, thermalexpansion, ultra violet light exposure and is strong enough for a personto walk on without deforming or losing it's original structure. Curingtime can vary as a function of temperature, weather, water loading andbinder type and content. In cases of where the invention is practiced incool, damp or wet environments, curing can take as long as ten days andstill result in a suitable constructive medium. On average, curing takesbetween 24 and 36 hours.

Once cured, the individual biomass pieces within the biomass constructare bound together, forming a protective ground cover that is porous(52) and breathable. The cementitious binder containing slurry binds tothe soil (54), terrain features such as topographic changes (56), rocks(58), vegetation (60) and existing features (62) while allowing thenatural flow of water to ensue while providing an environment forre-vegetation (64) and both vegetation and microbe growth. The biomassconstruct can be rewetted over periods of months and still retain itsbasic initial form with no degradation. Rewetting occurs when thebiomass construct, after it has cured, is subjected to water. Typicallyrewetting occurs via precipitation, dew, snow and/or wet weather. Thecured biomass construct forms an open weave three-dimensionalmorphology. The open weave morphology of the erosion control mediumpromotes water flow and water retention. Increased water retentionpromotes germination and rooting of vegetation (60), and the healthygrowth of micro-organisms. The erosion control medium also protects theground surface from the impact of rain and the effects of wind.

It should be understood that the final product produced from thedescribed methods produces a substantially homogeneous product. For thepurposes of this specification, “substantially homogeneous” means thatsubstantially the same ratio of components may be found throughout anapplicable blended mulch product, slurry, erosion control medium,construction product or biomass construct (as the case may be). Theratio of components should be generally consistent regardless of thecross-section, volume or amount of blended mulch product, slurry orerosion control medium examined. Small deviations, up to about 25%, inthe ratio are considered to be substantially homogenous. Preferably,blended biomass products, slurries and erosion control mediums only havedeviations up to about 20%. More preferably, blended biomass products,slurries and erosion control mediums only have deviations up to about15%. Large clumps are a common source of non-homogenous portions ofblended mulch products, slurries and erosion control mediums. Largeclumps of biomass have not been shown to have deleterious effects in anyof the envisioned applications.

In another alternative, dry mixing of the biomass, binder and anyadditives prior to the addition of water can be accomplished with asmall reduction in the optimal behavior characteristics of any slurryproduced and the in the resulting physical properties of the curedbiomass construct. Though dry blending can affect the resulting product,it is a viable approach to preparing the described biomass construct.

Furthermore, the biomass construct is a porous layer of material, whichcan capture blown seeds and soil. Blowing materials may be the productof natural occurrences or the resultant of human intervention. Theability to trap materials builds soil content and encouragesre-vegetation of eroded areas. Vegetative growth experiments have proventhe ability of grass seed to germinate and penetrate a cured biomassconstruct confirming that the innovation would not impede re-vegetationof eroded terrain.

The described biomass construct does not require the addition of anysynthetic additives such as screens, structural elements, positioningelements, securing elements or the like. Optionally, other materialssuch as seeds, fertilizers, biological materials, spores, lime or otherdesired additives may be added to biomass blends or biomass slurries,prior to the addition of water or after the addition of water. Suchadditives are known in the art and facilitate a wide variety of ownerbenefits.

A variety of additional aspects and characteristics of the presentinvention are described below, in addition to the various aspects andcharacteristics discussed above in this specification. Furthermore, aswith the aspects and characteristics described above, each of thefollowing aspects and characteristics individually and in variouscombinations provides a beneficial enhancement and is an embodiment ofthe present invention.

In one aspect, there is provided a biomass construct formed from ablended mixture comprising a blended biomass product, cementitiousbinder and water. The biomass construct comprises between 25% to 90% byweight of the cured biomass construct described herein. More preferably,the biomass material comprises between 50% to 85% by weight of the curedbiomass described herein. The biomass construct also includes acementitious binder that comprises between 10% to 75% by weight of thecured biomass product described herein. More preferably, thecementitious binder comprises between 15% to 50% by weight of the curedbiomass construct. The biomass and the cementitious binder are mixedwith water, which comprises between 5% to 55% water by weight of thetotal weight of the binder used to construct the biomass construct. Morepreferably, the amount of water comprises between 15% and 45% by weightof the total weight of the cementitious binder used to construct thebiomass construct. The water used in the preparation process is removedfrom the biomass construct upon curing resulting in a hard and toughbiomass construct. In this aspect, the biomass construct forms asubstantially homogenous open weave construct on the ground or surfaceto which it is applied.

In another aspect, there is provided a biomass construct, formed fromspray-application on the ground surface of a slurry mixture comprising ablended biomass product, binder and water. The biomass constructcomprises between 25% to 90% by weight of the cured biomass constructdescribed herein. More preferably, the biomass material comprisesbetween 50% to 85% by weight of the cured biomass described herein. Thebiomass construct also includes a cementitious binder that comprisesbetween 10% to 75% by weight of the cured biomass product describedherein. More preferably, the cementitious binder comprises between 15%to 50% by weight of the cured biomass construct. The biomass and thecementitious binder are mixed with water which comprises between 5% to55% water by weight of the total weight of the binder used to constructthe biomass construct. More preferably, the amount of water comprisesbetween 15% and 45% by weight of the total weight of the binder used toconstruct the biomass construct. The water used in the preparationprocess is removed from the biomass construct upon curing resulting in ahard and tough biomass construct. In this aspect, the biomass constructforms a substantially homogenous open weave construct on the ground orsurface to which it is applied.

In another aspect said biomass constructs can be formed into a varietyof predefined shapes and allowed to cure. Upon curing said predefinedshapes retain the aforementioned performance benefits as well as thepredefined shapes. The biomass construct comprises between 25% to 90% byweight of the cured biomass construct described herein. More preferably,the biomass material comprises between 50% to 85% by weight of the curedbiomass described herein. The biomass construct also includes acementitious binder that comprises between 10% to 75% by weight of thecured biomass product described herein. More preferably, thecementitious binder comprises between 15% to 50% by weight of the curedbiomass construct. The biomass and the binder are mixed with water,which comprises between 5% to 55% water by weight of the total weight ofthe binder used to construct the biomass construct. More preferably, theamount of water comprises between 15% and 45% by weight of the totalweight of the binder used to construct the biomass construct. The waterused in the preparation process is removed from the biomass constructupon curing resulting in a hard and tough biomass construct. In thisaspect, the biomass construct forms a substantially homogenous openweave construct on the ground or surface to which it is applied.

Although this invention has been described with reference toillustrative and preferred embodiments of carrying out the invention,this description is not to be construed in a limiting sense. Variousmodifications of form, arrangement of parts, steps, details and order ofoperations of the embodiments illustrated, as well as other embodimentsof the invention, will be apparent to persons skilled in the art uponreference to this description. It is therefore contemplated that theappended claims will cover such modifications and embodiments as fallwithin the true scope of the invention.

Example 1

An electric drill (24) of a type commonly used to mix paints was used tomix 5.7 pounds of MgCl cementitious binder in 3.6 pounds of water (20)in a 5 gallon plastic container (28). Said cementitious binder wasagitated for one and a half minutes using a mixing paddle (26) of thetype commonly used to mix paint and an electric drill (24) resulting ina homogeneous cementitious binder slurry (22). It should be understoodthat mixing times can vary as a function of water temperature, theamounts being mixed, the means for mixing, elevation and the type ofbinder used. 6.3 pounds of MgO was added as an additive (16) to thecementitious binder slurry (22) and mixed as previously describedresulting in a homogeneous mixture of all components called acementitious binder containing slurry (30). The cementitious bindercontaining slurry (30) was mixed with one cubic foot of biomass (2) in acement mixer resulting in fully coating said biomass with saidcementitious binder containing slurry. In terms of cubic feet, one cubicfoot of biomass was combined with 0.16 cubic feet of MgO, 0.14 cubicfeet of MgCl and 0.06 cubic feet of water.

Said coated biomass was applied to the application surface by manualmeans using a 5-gallon bucket. The resulting biomass construct curedover a period of 24 hours resulting in an erosion control barrier ofapproximately 1.36 cubic feet. Said cured biomass construct was endowedwith the exemplary strength, hardness and structural integrity.

Example 2

A sloped area fifty feet wide (66) and two hundred feet long (68) wastreated with biomass constructs (70) used as erosion control media. Theslope area had the remnants of some installed and previously failedwattles and straw bales (72). Other than these remnants the slope wasbarren with no major rocks, trees or topographic features through outthe treated area.

Level contour lines (74) were surveyed at approximate ten-foot intervalsdown the slope. Several contours were adjusted up or down the slope tooptimize the placement of the erosion control media. An optimizedplacement is one that considers the speed and power at which water movesduring an eroding process. As an example, areas of increased slope, forinstance a slope steeper than 20 degrees, require shorter distances orintervals between the placement of erosion control media. Areas thathave both steep slope and constrained terrain, such as a small ravinetwo feet wide and three feet deep, may require a thicker layer oferosion control media. Areas of ground that have slight slopes, forinstance a slope of less than ten degrees, may require smaller amountsof erosion control media spaced farther apart, i.e. larger intervalsbetween contour lines (74).

In this example a total of nineteen erosion control barriers were placedacross a slope. Each barrier spanned the width of the erosion prone zoneand had an approximate length of fifty feet at the narrowest and seventyfive feet at the widest area being treated. The barriers where placedparallel to one another taking into consideration small variations inslope as previously described and more or less followed a consistentelevation across the slope. The barriers where placed such that anyerosive flow impacted the barrier did so perpendicular to the barriersorientation to the slope. Three contours were found to be identical topreviously installed wattles and straw bales. The erosion controlbarriers produced incorporated the remnants of the previously installedwattles and straw bales with no degradation of resulting performance.

The erosion control barriers in this example where produced by combining800 cubic feet of Ponderosa pine woodchips, 100 cubic feet of compostedwoody biomass, binder components, and 44 cubic feet of water aspreviously described.

Example 3

In another example 570 pounds of MgCl, 630 pounds of MgO, 5.5 cubic feetof foam, 1200 pounds of biomass and 342 gallons of water where combinedto produce biomass constructs for use as erosion control barriers (76).The materials where combined as previously described and positioned byhand in a series of ravines (78) facilitating erosion control.

Example 4

Water penetration is an important performance variable as it relates theamount of water that penetrates the soil versus the amount of waterrunning off the eroding slope on top of or through the upper layer ofbiomass construct. In order to assess the performance of the saidbiomass construct, an inclined rainfall simulation test bed wasconstructed. Said test bed was built to conform to the designspecifications published on the Texas Department of Transportation(TXDOT) testing facility website. The test bed had a length of 15 feetand a width of 2.5 feet and was constructed using hydraulic cylinders toachieve different target inclines. The soil used in the test bed wasnative to New Mexico and known to be highly erodible.

Using said test bed, a control was established by evaluating soil losson soil with no installed erosion control barrier. In the case of noerosion control barrier, a substantial amount of soil was lost, theequivalent of approximately 9.5 tons per acre, and large channels wereformed in the eroded soil. Once the soil dried, a biomass construct suchas that described in example 1, was produced and applied to thepreviously eroded bed. The biomass construct was allowed to cure on saidtest bed. Once the biomass construct was fully cured, the test bed wassubjected to three rain cycles of 30 minutes each. Each rainfall eventwas equivalent to three 3.5 inch per hour rainfall events. Sediment losswas evaluated as described in the Texas Department of Transportationprocedures as follows. All water and sediment was collected in a tank atthe base of the sediment bed. The sediment was allowed to settle for aminimum of 12 hours. Once settled, the clear water was drawn off. Theremaining sediment and water was removed from the sediment tank andweighed. Weight was taken to the nearest 0.1 lb. Sediment was agitatedfor two minutes and then 10 samples were taken. Samples were transferredto a desiccating oven and dried. Sediment loss was calculated bydetermining the water (w) to sediment (s) mass ratio (w/s). This ratiowas applied to the full sediment sample to determine total sedimentloss. Several trials were run using the biomass construct on saiderodible soil. Each test showed no sediment loss, at the most aggressiveincline of 2:1, no additional soil was lost and the amount of surfacerunoff was reduced by more than 22% indicating that the sloped soil wasnot only stabilized, but also benefited from increased waterpenetration, that is, percolation of water into the soil which is knownto be beneficial to animals and plants alike.

Example 5

A further important parameter is the strength of the cured biomassconstruct. In order to assess strength versus biomass constituent ratio,a series of formulation derivatives where prepared and evaluated by adesign of experiments. The metric used to evaluate strength was the psicompressive force required to achieve ⅛ of an inch compression on thecured biomass construct. The results of the compression test arepresented in table 1.

TABLE 1 Biomass constituent ratios versus Strength (in psi compressiveforce to achieve ⅛ inch compression). Test Adjusted Strength numberBiomass MgO MgCl Water MgCl2—6H20 H20 (PSI) 10  100 68 32 105 68 69 150(control) 5 75 50 40 160 85 115 150 2 125 50 24 160 51 115 25 3 75 11224 160 51 115 175 7 75 112 40 78 85 35 120 4 125 112 24 78 51 38 0 8 125112 40 160 85 115 110 9 100 68 32 105 68 69 120 (control) 6 125 50 40 7885 35 60 1 75 50 24 78 51 38 100

Results from the design of experiments suggested a formulation ratio tobe 1 gram of magnesium hydroxide to 1-gram magnesium chloridehexahydrate, 2 grams water to 3 grams of biomass to produce biomassconstructs with exceptional strength characteristics.

Although the present invention has been described in considerable detailwith reference to certain preferred versions thereof, other versions arepossible. Therefore, the spirit and scope of the appended claims shouldnot be limited to the description of the preferred versions containedherein.

NUMERICAL IDENTIFICATION

-   -   2 Biomass    -   4 Trees    -   6 Twigs    -   8 Ground    -   10 Binder containing slurry in cured form    -   12 Cementitious binder    -   14 Admixtures    -   16 Additives    -   18 Foam    -   20 Water    -   22 Cementitious binder slurry    -   24 Electric drill    -   26 Mixing paddle    -   28 Five gallon bucket    -   30 Cementitious binder containing slurry    -   32 Mechanical mixer    -   34 Binder coated biomass    -   40 Blower    -   42 Application surface    -   44 Static mixing nozzle    -   46 Ball valve    -   48 Injection ports    -   50 Biomass construct    -   52 Porous    -   54 Soil    -   56 Topographic changes    -   58 Rocks    -   60 Vegetation    -   62 Existing features    -   64 Vegetation    -   66 50 feet wide    -   68 200 feet long    -   70 Biomass constructs    -   72 Previously failed wattles and straw bales    -   74 Contour line    -   76 Erosion control barriers    -   78 Ravine

What is claimed is:
 1. A process for preparing a solid biomass constructfor application to a ground surface in order to reduce erosion,comprising the steps of: (a) formulating a cementitious binder; (b)thoroughly mixing said cementitious binder in a quantity of water so asto form a cementitious binder slurry; (c) adding said cementitiousbinder slurry to a quantity of biomass and thoroughly mixing said slurryand said biomass together so as to substantially coat said biomass withsaid slurry; (d) applying said slurry coated biomass to said groundsurface; and (e) allowing said slurry coated biomass applied to saidground surface to cure into a solid biomass construct.
 2. The processaccording to claim 1 wherein said biomass is substantially derived fromsources local to said ground surface.
 3. A solid biomass constructproduced by the process according to claim
 1. 4. The process accordingto claim 1 wherein said cementitious binder includes one or morechemicals chosen from the group consisting of magnesium oxide, magnesiumoxychloride, magnesium oxysulfate, magnesium phosphate, and a mixturethereof.
 5. The process according to claim 1 wherein said step offormulating said cementitious binder includes means for increasing thestrength, hardness, and tensile strength of said solid biomass construct6. The process according to claim 1 wherein said steps of (a), (b), (c),(d), and (e) include means for creating a porous structure within saidsolid biomass construct.
 7. The process according to claim 1 whereinsaid biomass comprises between 25% to 90% by weight of said cured, solidbiomass construct.
 8. The process according to claim 7 wherein saidbiomass comprises between 50% to 85% by weight of said cured, solidbiomass construct.
 9. The process according to claim 1 wherein saidcementitious binder comprises between 10% and 75% by weight of saidcured, solid biomass construct.
 10. The process according to claim 9wherein said cementitious binder comprises between 15% to 50% by weightof said cured, solid biomass construct.
 11. The process according toclaim 1, further comprising the step of adding a foaming agent duringsaid step of thoroughly mixing said cementitious binder in said quantityof water.
 12. The process according to claim 11 wherein said step ofadding a foaming agent comprises adding said foam in volumetric ratiosbetween 1 part foam to 1 part cementitious binder slurry, to 2 partsfoam to 1 part cementitious binder slurry.